This invention relates to a keyboard musical instrument and, more particularly, to a keyboard musical instrument for automatically playing a tune without fingering on the keyboard and a key actuating device incorporated therein.
An automatic player piano is an example of the keyboard musical instrument for automatically playing a tune without fingering on the keyboard. The automatic player piano is usually broken down into an acoustic piano and an automatic playing system. A standard upright piano or a standard grand piano is used as the acoustic piano. A key actuating device and a controller are incorporated in the automatic playing system. Plural solenoid-operated key actuators are arrayed in two rows in a staggered fashion, and are assembled with a framework. The framework is fixed to the key bed of the acoustic piano, and the plural solenoid-operated key actuators are opposed to the rear portions of the black/white keys.
When a user instructs the controller to play a tune, the controller acquires a set of music data codes representative of the tune, and gets ready for an automatic performance. The controller is sequentially interpreting the music data codes of the set, and selectively energizes the solenoid-operated key actuators. When the solenoid-operated key actuators are energized, the solenoids generate magnetic fields, and the plungers project from the associated solenoids so as to push the rear portions of the associated black/white keys. Then, the key action mechanisms are actuated, and the hammers are driven for free rotation toward the associated strings. The hammers strike the associated strings at the ends of the free rotations. The strings vibrate, and generate the piano tones. Thus, the automatic playing system plays the tune on the keyboard without any fingering.
A typical example of the key actuator device is disclosed in Japanese Patent Publication of Unexamined Application No. 9-237082. FIGS. 1 and 2 show the prior art automatic player piano equipped with the key actuating device. Reference numeral 100 designates a key actuating device. An acoustic piano has a key bed 101, and a slot 102 is formed in the key bed 101. A key frame is mounted on the key bed 101, and plural black/white key 103 are rotatably supported by a balance rail (not shown) on the key frame. The black/white keys 103 form in combination a keyboard. The slot 102 is located under the rear portions of the black/white keys 103, and is prolonged in the lateral direction of the key bed. The lateral length of the slot 102 is not shorter than the width of the keyboard, and the key actuating device 100 is opposed to the rear portion of the keyboard in the slot 102.
The key actuating device 100 is broken down into a framework 110 and array of solenoid-operated key actuator units 120. The solenoid-operated key actuator units 120 are respectively associated with the black/white keys, and are fixed to the framework 110. The framework 110 is secured to the key bed 101, and keeps the array of solenoid-operated key actuator units 120 in the slot 102. The solenoid-operated key actuator units 120 are retained under the rear portions of the black/white keys 103, and are respectively aligned with the rear portions.
The framework 110 is broken down into a base plate 111, a center wall 112 and a bracket 113. The bracket 113 is formed with a hole as long as the slot 102, and is screwed to the lower surface of the key bed 101 so that the holes underlies the slot 102. Holes are formed in the brackets at intervals. The base plate 111 has a land portion and a pair of fins. The land portion has a cross section like an inverted U-letter, and a slit is formed in the land portion. The fins outwardly project from the both sides of the land portion, and holes are formed in the fins at intervals. The land portion is as long as the slot 102, and is narrower than the slot 102. When the land portion is inserted into the slot 102, the brackets 113 is underlain by the side fins, and the holes formed in the brackets 113 are aligned with the holes formed in the fins. Bolts are screwed into the holes so as to fix the base plate 111 to the bracket 113. The bracket 113 keeps the upper surface of the land portion close to the lower surface of the key bed 101.
The center wall 112 has a cross section like a mirror image of L-letter. The vertical portion of the center wall 112 passes through the slit, and the horizontal portion of the center wall 112 underlies the lower surface of the land portion. The horizontal portion of the center wall 112 is fixed to the land portion, and a rigid circuit board is hung from the horizontal portion of the center wall 112. The vertical portion of the center wall 112 is upright on the land portion, and projects into the slot 102. Though not shown in the figures, holes are formed in thee vertical portion at intervals, and are elongated in the vertical direction.
Each of the solenoid-operated key actuator unit 120 includes a yoke 121, a solenoid 122 and a plunger 123. The solenoid-operated key actuator units 120 are arranged in two rows, i.e., the front row and the back row. The yokes 121 of the solenoid-operated key actuator units 120 in the front row are fixed onto the front surface of the vertical portion by means of bolts 125. The bolts 125 are inserted into the elongated hole, and are screwed into threaded holes formed the yoke 121. The yokes 121 of the solenoid-operated key actuator units 120 in the back row are fixed to the back surface of the vertical portion in a staggered manner with the yokes on the front surface by means of the bolts 125 as shown in FIG. 2. For this reason, even if the solenoid-operated key actuator units 120 have relatively large solenoids 122, the yokes 121 permit the plungers 123 to be aligned with the relatively thin black/white keys 103, respectively. The bolts 125 pass through the elongated holes, and are screwed into the threaded holes formed in the yoke 121 on the back surface of the vertical portion.
The yoke 121 is splitable into a lower plate and an upper plate, and a hollow space takes place between the lower plate and the upper plate. The solenoid 122 is accommodated in the hollow space, and is pinched therebetween. The solenoids 122 are connected to electric components arranged on the rigid circuit board. The plunger 123 is inserted into the solenoid, and is projectable from the solenoid 122. The leading end of the plunger is in proximity of the lower surface of the associated black/white key 103. When electric current flows through the solenoid 122, magnetic field is created so that the plunger 123 projects upwardly. The upward motion of the plunger 123 gives rise to the rotation of the associated black/white key 103 around the balance rail.
The solenoid-operated key actuator units 120 are assembled with the center plate 112 as follows. First, the center wall 112 is assembled with the base plate 111. Subsequently, the yoke 121 is moved on one of the front/back surfaces of the vertical portion, and the threaded holes of the yoke 121 are roughly aligned with the elongated holes of the vertical portion. The yoke 121 is vertically moved along the elongated holes so as to place the leading end of the plunger 123 at the appropriate position close to the lower surface of the rear portion of the associated black/white key 103. The bolt holes of the yoke 121 are strictly aligned with the elongated holes of the vertical portion without changing the gap between the plunger 123 and the associated black/white key 103, and the bolts 125 are inserted from the other of the front/back surfaces through the elongated holes into the threaded holes. The bolts 125 are screwed into the threaded holes, and presses the yoke 121 against the front/back surface.
Subsequently, the yoke 121 is moved to the other of the front/back surfaces of the vertical portion, and the threaded holes of the yoke 121 are roughly aligned with the elongated holes of the vertical portion. The yoke 121 is vertically moved along the elongated holes so as to place the leading end of the plunger 123 at the appropriate position close to the lower surface of the rear portion of the associated black/white key 103. The bolt holes of the yoke 121 are strictly aligned with the elongated holes of the vertical portion without changing the gap between the plunger 123 and the associated black/white key 103, and the bolts 125 are inserted from the other of the opposite surface through the elongated holes into the threaded holes. The bolts 125 are screwed into the threaded holes, and presses the yoke 121 against the back/front surface.
Other yokes 121 are alternately fixed onto the front surface and the back surface in the staggered manner. As a result, the solenoid-operated key actuator units 120 are arranged in the two rows on the front/back surfaces of the vertical portion of the center wall 112. The head portions of the bolts 125 are sandwiched between the yokes 121 on the front/back surfaces of the vertical portions.
A problem is encountered in the prior art key actuating device in that a large amount of time and labor is consumed in the assemblage. As described hereinbefore, the center plate 112 is assembled with the base plate 111. Thereafter, the solenoid-operated key actuator units are alternately fixed onto the front/back surfaces of the vertical portion of the center wall 112, and are individually adjusted to the appropriate positions. The adjusting work and the assembling work are time-consuming, and the production cost of the automatic player piano is increased.
Another problem inherent in the prior art key actuating device 100 is a poor repairablity. In other words, any one of the solenoid-operated key actuator units 120 except those at both sides of the rows is hardly changed to a new solenoid-operated key actuator unit 120. This is because of the fact that the gap between the adjacent yokes 121 are too narrow. A worker can not insert a tool into the gap. If one of the solenoid-operated key actuator units 120 is damaged, the worker is to disassemble all the solenoid-operated key actuator units 120 on either side of the damaged solenoid-operated key actuator unit 120 and assemble and adjust them, again. Thus, the user suffers from high repairing cost.
It is therefore an important object of the present invention to provide a key actuating device, actuator units of which are easily assembled thereinto without consuming a large amount of time and labor.
It is also an important object of the present invention to provide a keyboard musical instrument equipped with the key actuating device.
In accordance with one aspect of the present invention, there is provided an actuating device for actuating plural members comprising a retainer having a longitudinal direction and formed with a guide extending in the longitudinal direction, plural actuators having sliding portions engageable with the guide so as to be moved in the longitudinal direction, and a fastener provided between the plural actuators and the retainer, and securing the plural actuators at target positions.
In accordance with another aspect of the present invention, there is provided a keyboard musical instrument for generating tones comprising plural keys arranged in a lateral direction on a stationary board and moved with respect to the stationary board for specifying pitches of the tones to be generated, a tone generator responsive to the motions of the plural keys for generating the tones, and a key actuating device provided in the vicinity of the plural keys for selectively moving the plural keys without fingering of a human player and including a retainer elongated in the lateral direction and formed with a guide extending in the lateral direction, plural actuators having sliding portions engageable with the guide so as to be moved in the lateral direction and a fastener provided between the plural actuators and the retainer and keeping the plural actuators at target positions in proximity to the plural keys, respectively.